1. Field of the Invention
The present invention relates to a mobile communications system, and more particularly, to a multi-mode mobile terminal and method of triggering a communication service using position information thereof, by which a communication mode can be triggered to support a plurality of communication services.
2. Discussion of the Related Art
Generally, in the currently established communication environment, not only one communication system but also various kinds of communication systems exist together, which means the various kinds of separate communication services are provided in the communication environment.
For instance, both of the code division multiple access (hereinafter abbreviated CDMA) communication service and the global system for mobile communication (hereinafter abbreviated GSM) service may be provided within a wide area.
For another instance, both of the CDMA communication service and the wideband code division multiple access (hereinafter abbreviated W-CDMA) communication service are provided together.
Thus, a multi-mode mobile terminal has been developed to fit the communication environment where various kinds of communications systems co-exist.
The multi-mode mobile terminal enables to utilize frequency bandwidths corresponding to a plurality of separate communication modes, respectively, thereby being equipped with a roaming function of switching from a communication mode supported by a specific communication system to another communication mode supported by another communication system.
Moreover, the multi-mode mobile terminal adopts an automatic triggering type and/or a manual triggering type in switching a communication mode for roaming.
The automatic triggering type multi-mode mobile terminal triggers its service (communication) method by itself according to presence or non-presence of reception of base station signals. The base station signals that will be explained in the following include electromagnetic wave strength, communication parameters, intrinsic identification (ID) of the base station, etc.
On the other hand, the manual triggering type multi-mode mobile terminal triggers its service (communication) method by a user's direct manipulation.
These two kinds of triggering methods are explained in detail in the following by taking a multi-mode mobile terminal enabling to utilize both CDMA and GSM communications systems as an example.
FIG. 1 is a flowchart of an automatic triggering method of a communication service according to a related art.
Referring to FIG. 1, it is assumed that a multi-mode mobile terminal operates in a CDMA communication mode communicating with a CDMA base station (S1).
The multi-mode mobile terminal keeps checking whether a signal is received from the CDMA base station (S2).
Once receiving the signal. from the CDMA base station, the multi-mode mobile terminal maintains the CDMA communication mode communicating with the CDMA base station.
Yet, if failing to receive the signal from the CDMA base station, the multi-mode mobile terminal triggers its communication mode (S3). Namely, the multi-mode mobile terminal switches the current communication mode to a GSM communication mode if not receiving a CDMA signal.
The multi-mode mobile terminal communicates with a GSM base station, accordingly (S4).
Thereafter, the multi-mode mobile terminal keeps checking whether a signal is received from the GSM base station (S5).
Once receiving the signal from the GSM base station, the multi-mode mobile terminal maintains the GSM communication mode communicating with the GSM base station.
Yet, if failing to receive the signal from the GSM base station, the multi-mode mobile terminal triggers its communication mode (S6). Namely, the multi-mode mobile terminal switches the current communication mode to the CDMA communication mode if not receiving a CDMA signal.
And, the multi-mode mobile terminal communicates with the CDMA base station (S1), accordingly.
FIG. 2 is a flowchart of a manual triggering method of a communication service according to a related art.
Referring to FIG. 2, it is assumed that a multi-mode mobile terminal operates in CDMA communication mode communicating with a CDMA base station (S10).
Moreover, it is also assumed that a user of the multi-mode mobile terminal has moved away into another area and that the user already knew a communication mode of the area where he has moved. For example, the user carrying the multi-mode mobile terminal operating in the CDMA communication mode has moved away into B-area from A-area and the user already recognized that the communication mode in the B-area is GSM.
The user should manually manipulate the multi-mode mobile terminal to select the communication mode of the B-area where he has moved.
The multi-mode mobile terminal confirms presence or non-presence of user's selection of the communication mode (S11). The multi-mode mobile terminal confirms the presence or non-presence of the user's selection of the GSM communication mode since the CDMA communication mode is currently used.
If the user selects the communication mode of the B-area, the multi-mode mobile terminal operates in the communication mode selected by the user.
Once the user having moved to the B-area, as explained in the above-example, selects the GSM communication mode, the multi-mode mobile terminal operates in the GSM communication mode to communicate with the GSM base station.
In brief, the multi-mode mobile terminal roams to the GSM base station supporting the GSM communication mode selected by the user (S12).
Thereafter, the user should select the communication mode by manually manipulating the multi-mode mobile terminal.
The multi-mode mobile terminal checks presence or non-presence of user's selection of the communication mode (S13). The multi-mode mobile terminal confirms the presence or non-presence of the user's selection of the CDMA communication mode since it is currently roamed to the GSM communication mode.
If the user selects another communication mode, the multi-mode mobile terminal operates in the communication mode selected by the user.
Once the user having moved to the B-area, as explained in the above-example, returns to the A-area to select the CDMA communication mode, the multi-mode mobile terminal operates in the CDMA communication mode to communicate with the CDMA base station.
In brief, the multi-mode mobile terminal roams to the CDMA base station supporting the CDMA communication mode selected by the user (S14).
As explained in the above description, the multi-mode mobile terminal triggers the communication mode enabling to receive the base station signal in selecting the communication mode for roaming.
The multi-mode mobile terminal generally uses the automatic triggering method together with the manual triggering method. Namely, the multi-mode mobile terminal holds user's communication mode selection as well as automatically triggers the communication mode according to the presence or non-presence of the reception of the base station signal.
However, if the related art multi-mode mobile terminal is located in a place of poor reception of the base station signal such as a basement and a shadow zone. It has a problem in repeating the communication mode triggering to select one of supportable communication modes. This is because the multi-mode mobile terminal adopts the automatic triggering method.
For instance, if the related art multi-mode mobile terminal is operative in CDMA communication mode, W-CDMA communication mode, or GSM communication mode, it automatically triggers the CDMA communication mode on receiving CDMA base station signal, the W-CDMA communication mode on receiving W-CDMA base station signal, or the GSM communication mode on receiving GSM base station signal.
Yet, when the multi-mode mobile terminal is located in the area enabling both receptions of the CDMA and GSM base station signals, the communication mode triggering frequently takes place in the multi-mode mobile terminal unnecessarily. This considerably stands in the way of user's communications.
Although one specific communication mode manually selected by a user is intended to maintain, if temporary failure is caused to the multi-mode mobile terminal so that the multi-mode mobile terminal is unable to receive a base station signal in a currently set communication mode, the current communication mode is automatically switched to another communication mode to receive base station signals in another communication mode. This behavior confuses the user's communication mode selection and may make the user unable to recognize what is the current mode.
Meanwhile, in case that the related art multi-mode mobile terminal adopts the manual triggering method, the user may select a wrong communication mode. Namely, a user of a multi-mode mobile terminal is unable to know the exact communication mode fitting each area. For that reason, the user intends to maintain the previously selected communication mode despite his wrong selection of the communication mode for the currently located area once the communication mode is selected, thereby failing to be supported by the most appropriate communication mode to be unable to smoothly communicate. Keeping operating in the currently selected communication mode, the multi-mode mobile terminal may be unable to receive the corresponding base station signals and its communication may be cut off.
For instance, let us assume that a multi-mode mobile terminal operating in GSM communication mode has moved to an area governed by the CDMA communication mode. If a user fails to recognize that the current area is governed by the CDMA communication mode, the multi-mode mobile terminal keeps trying to receive GSM base station signals impossible to receive. Consequently, it is impossible for the multi-mode mobile terminal to communicate in the current area governed by the CDMA communication mode.